Cambridge A Level Biology 9700 — 2010 May/June Paper 3 · Variant 5

This document consists of 11 printed pages and 1 blank page. DC (AC/SW) 15999/5 © UCLES 2010 [Turn over UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Advanced Subsidiary Level and Advanced Level READ THESE INSTRUCTIONS FIRST Write your Centre number, candidate number and name on all the work you hand in. Write in dark blue or black pen. You may use a pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Answer all questions. At the end of the examination, fasten all your work securely together. The number of marks is given in brackets [ ] at the end of each question or part question. You are advised to spend one hour on each question. * 8 4 1 9 0 0 7 0 5 0 * BIOLOGY 9700/35 Paper 31 Advanced Practical Skills May/June 2010 2 hours Candidates answer on the Question Paper. Additional Materials: As listed in the Confidential Instructions For Examiner’s Use 1 2 Total

9700/35/M/J/10 © UCLES 2010 For Examiner’s Use You are reminded that you have only one hour for each question in the practical examination. You should read carefully through the whole of each question and then plan your use of the time to make sure that you finish all the work that you would like to do. You will gain marks for recording your results according to the instructions. 1 You are required to find the water potential of two solutions, A and B. The water potential of a plant tissue can be found by immersing the plant tissue in sucrose solutions of different water potential. Sucrose solutions A and B are the solutions in which tissues from two different species of plant did not change in mass after immersion for 30 minutes as shown in Fig. 1.1. sucrose solution plant tissue Fig. 1.1 (a) (i) Use two of the following words to complete the sentences below. gains less loses more If the plant tissue … water then the sucrose solution will become more dilute. This will change the solution so that it becomes … dense. [1] 2

3 9700/35/M/J/10 © UCLES 2010 [Turn over For Examiner’s Use A blue dye is added to the two solutions, A and B, so that they can be seen. A drop of the coloured solution is placed into a known concentration of sucrose solution. Fig. 1.2 shows how the drop is released. 5 cm3 syringe resting on top of large test-tube marker line where drop is released drop coloured solution gently press plunger to release a drop Fig. 1.2 Immediately the drop is released the syringe is removed. The drop may move up, move down or remain at the same level. (ii) Show clearly on the diagrams below how you would expect to see the drop move. sucrose solution drop drop more concentrated than solution drop same concentration as solution drop less concentrated than solution drop drop sucrose solution sucrose solution [2]

4 9700/35/M/J/10 © UCLES 2010 For Examiner’s Use You are provided with • 200 cm3 of 1.0 mol dm¯3 sucrose solution in a beaker, labelled S • 200 cm3 of distilled water in a beaker, labelled W • 10 cm3 of sucrose solutions A and B • 10 cm3 of 0.01% methylene blue, labelled D. If any methylene blue comes into contact with your skin wash off immediately with water. It is recommended that you wear safety goggles/glasses. To find the concentration of sucrose in samples A and B you will need to dilute the 1.0 mol dm¯3 sucrose solution to provide a range of concentrations. (iii) Decide on the concentrations of sucrose solution that you will prepare using the 1.0 mol dm¯3 sucrose solution and distilled water. You will need to make up 50 cm3 of each sucrose solution. Prepare the space below to show • the concentrations of sucrose solution • the volumes of 1.0 mol dm¯3 sucrose solution • the volumes of distilled water. [3]

5 9700/35/M/J/10 © UCLES 2010 [Turn over For Examiner’s Use Make up the sucrose solutions that you have chosen in the containers provided. 1. Place a 5 cm3 syringe on top of the large test-tube and use the glass marker to draw a line on the test-tube at the same height as the end of the syringe nozzle as shown in Fig. 1.2. 2. Use a 5 cm3 syringe to collect 4.0 cm3 of A and place it in a Petri dish. With a pipette, add sufficient drops of D to turn the solution blue and stir. 3. Use the same syringe to collect 1.0 cm3 of the coloured solution A. Wipe the syringe with a paper towel and label the syringe A. 4. Repeat steps 2 and 3 with sample B and label the second syringe B. 5. Put 35 cm3 of one of your sucrose solutions into the large test-tube. 6. As shown in Fig. 1.2, put syringe A into the large test-tube so the end of the nozzle is level with the mark. Hold the syringe vertically and very gently push out a drop of the coloured solution. 7. Immediately observe the movement of the drop. 8 Record your observations. 9. Repeat steps 6 to 8 with sample B in syringe B. 10. Empty and wash the large test-tube. 11. Repeat steps 5 to 10 with each sucrose solution that you have made and record all your observations.

6 9700/35/M/J/10 © UCLES 2010 For Examiner’s Use (iv) Prepare the space below to record your observations. [6] (v) Use your results to estimate the sucrose concentration of sample A …mol dm¯3 sample B … mol dm¯3. [2]

7 9700/35/M/J/10 © UCLES 2010 [Turn over For Examiner’s Use In order to find the water potential of the solutions A and B a graph is required showing the relationship between sucrose concentration and water potential. Table 1.1 shows the water potential of different sucrose concentrations. Table 1.1 sucrose concentration / mol dm¯3 water potential / kPa x 102 0.15 –5.0 0.35 –12.0 0.55 –19.0 0.75 –26.0 1.00 –35.0 (b) (i) Plot a graph of the data shown in Table 1.1. [4] (ii) Using your results and your graph estimate the water potential of sample A. Show clearly on your graph how you obtained the water potential. [1] water potential of sample A …[1]

8 9700/35/M/J/10 © UCLES 2010 For Examiner’s Use (iii) Describe how you would improve the investigation to obtain a more accurate estimate of the water potential of sample A. … … … … … … …[3] [Total: 23] 2 L1 is a slide of a stained transverse section of the trachea from a mammal. The slide shows the C-shaped ring of cartilage. (a) (i) Draw a large plan diagram of half of the trachea showing the ends of the cartilage ring. Label the diagram. [5]

9 9700/35/M/J/10 © UCLES 2010 [Turn over For Examiner’s Use Fig. 2.1 is a photomicrograph of a transverse section through a different tubular structure from an animal. X magnification x70 Fig. 2.1 (ii) Prepare the space below so that it is suitable for you to compare and contrast the specimens on slide L1 and in Fig. 2.1. Record your observations. [5]

10 9700/35/M/J/10 © UCLES 2010 For Examiner’s Use (iii) Calculate the actual distance across the lumen of the structure shown by line X in Fig. 2.1. Show all the steps in your calculation. [3] Fig. 2.2 shows a photomicrograph of structures labelled Z. Z Fig. 2.2

11 9700/35/M/J/10 © UCLES 2010 For Examiner’s Use (b) Make a large drawing of three of these structures, which must be complete, to show the differences between them. Draw a circle on Fig. 2.2 around each of the structures Z which you have drawn. [4] [Total: 17]

12 9700/35/M/J/10 © UCLES 2010 BLANK PAGE Copyright Acknowledgements: Figure 2.1 © P590/039; Biophoto Associates/Science Photo Library. Figure 2.2 © M112/039; London School of Hygiene and Tropical Medicine/Science Photo Library. Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. University of Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.

UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS GCE Advanced Subsidiary Level and GCE Advanced Level MARK SCHEME for the May/June 2010 question paper for the guidance of teachers 9700 BIOLOGY 9700/35 Paper 31 (Advanced Practical Skills 1), maximum raw mark 40 This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes must be read in conjunction with the question papers and the report on the examination. • CIE will not enter into discussions or correspondence in connection with these mark schemes. CIE is publishing the mark schemes for the May/June 2010 question papers for most IGCSE, GCE Advanced Level and Advanced Subsidiary Level syllabuses and some Ordinary Level syllabuses.

Page 2 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 35 © UCLES 2010 Question Expected Answers Additional Guidance Marks 1 (a) (i) Complete the sentences: If the plant tissue ….. water then the sucrose solution will become more dilute. This will change the solution so that it becomes ……dense. ACE conclusion 1 loses and less; [1] (ii) Show clearly on the diagrams below how you would expect to see the drop move. (same concentration/middle tube) drop stays at same height/no movement; [1] ACE conclusion 2 (more concentrated/left tube) shows drops/sinks/falls (less concentrated/right tube) AND rises; [1] (iii) Decide on the concentrations of sucrose solution. Prepare the space below to show concentrations of sucrose solution; volumes of 1.0 mol dm-3 sucrose solution; volumes of distilled water. three concentrations; [1] even range; [1] MMO decisions 3 correct volumes to make 50 cm3 AND correct molarity; [1]

Page 3 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 35 © UCLES 2010 Question Expected Answers Additional Guidance Marks (iv) Prepare the space below to record your observations. table with cells drawn no outer boundary (heading to top/left) AND conc(entration)/mol dm-3; [1] (headings) (syringe) A AND (syringe) B; [1] PDO recording 3 (records) description or key to show movement; [1] A (0.7 mol dm-3) moves up and down; [1] MMO collection 2 B (0.25 mol dm-3) moves up in molarities more than 3 and down in others; [1] MMO decision 1 records more than one drop for each concentration; [1] (v) Use your results to estimate the sucrose concentration. (A) correct with their results; [1] ACE interpretation (B) correct with results; [1]

Page 4 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 35 © UCLES 2010 Question Expected Answers Additional Guidance Marks (b) (i) Plot a graph of the data shown in Table 1.1. O x-axis [sucrose] or conc mol dm-3/M/molar y-axis AND water potential/Ψ kPa x102; Must have units [1] S scale as 0.2 to 2 cm (allow no 0) ECF if no labels or incorrect on axes for O AND negative 0 at top –10 to 2 cm; Reject if awkward scale [1] P correct plotting using crosses or dot in circle; Intersection of cross must be clear to show plot Reject plotting if scale is awkward or if only blobs/dots/blobs in circles [1] PDO layout 4 0.15 –5.0 0.35 –12.0 0.55 –19.0 0.75 –26.0 1.00 –35.0 L ruled/straight line through points; Quality – not thick, not feathery for the complete line Joining plots – • Ruled lines plot to plot • Straight line through most plots • Straight line extrapolated to 0 Extrapolation not beyond x- or y-axis Reject if not five plots [1]

Page 5 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 35 © UCLES 2010 Question Expected Answers Additional Guidance Marks (ii) Using your results and your graph estimate the water potential of sample A (0.70). MMO collection 1 (using their result for A) shows clearly on graph how one water potential obtained; Allow any indication but must be estimate of A [1] ACE interpretation 1 any correct reading of water potential(s) AND kPa x102; If A between … and …. reads off two water potentials allow any correct Allow if correct with result and reading from graph [1] (iii) Describe how you would improve the investigation to obtain a more accurate estimate of the water potential of sample A. more (sucrose) solutions of known water potential; two further examples of concentration of sucrose or describes more around where drop drops and rises; more sucrose solutions or concentrations to estimate A; standardise the volume of the methylene blue dye OR suggests method for controlling volume of drop; ACE improvement 3 method to introduce drop OR measure time to rise or sink; [max 3] Total [23]

Page 6 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 35 © UCLES 2010 Question Expected Answers Additional Guidance Marks 2 (a) (i) Draw a large plan diagram of half of the trachea showing the ends of the cartilage ring. Label the diagram. Reject all marks except label if only 1 line. PDO layout 1 clear, sharp, unbroken lines AND no shading AND large; Minimum of three lines [1] no cells AND drawn only half; Minimum of two lines. [1] MMO collection 2 (in half section) has at least two ends of cartilage ring; [1] at least 6 lines for layers; [1] MMO decision 2 Reject if any label is biologically incorrect e.g. cell wall Reject if any labels from other tissues e.g. arteries, veins, plant tissues and named cells unless described as a layer Accept any one label with label line correct cartilage epithelium (smooth) muscle layer of Goblet/mucus cells lumen; Reject if overlaps text in question Reject if any writing on drawing [1]

Page 7 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 35 © UCLES 2010 Question Expected Answers Additional Guidance Marks (ii) Prepare the space below so that it is suitable for you to compare and contrast the specimens on slide L1 and in Fig. 2.1. PDO recording 1 organised as AND table/venn diagram/ruled connected boxes correctly headed AND comparative statements opposite each other; L1 Fig 2.2 [1] MMO collection 1 lumen clearly identified as present in both; [1] feature: L1 (trachea): Fig. 2.1: (bronchiole) then three of: 1.lumen shape or lining regular/circular not folded/no villi irregular/not circular folded/villi; 2. cilia or brush border microvilli present cilia/brush border absent or not visible microvilli; 3. cartilage present absent; 4. surrounding cells/air sacs/spaces absent or no(ne) present or have; 5. epithelium thinner/narrower thicker/wider; 6. goblet or mucus cells present or visible absent or not visible; 7. size wider/larger narrower/smaller; ACE interpretation 3 8. whole shape similarities: smooth muscle oval/triangular (whole shape) round/circular round/circular; Ticks and crosses requires a key Reject 3D, disc or spherical or arbitrary or random Reject negatives e.g. not circular Reject opposites e.g. regular [max 3]

Page 8 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 35 © UCLES 2010 Question Expected Answers Additional Guidance Marks (iii) Calculate the actual distance across the lumen of the structure shown by line X in Fig. 2.1. MMO collection 1 measures line X correctly in mm or cm Reject m [1] shows their measurement divided by or / or ÷ 70 AND × 1000 or 103 (mm) or 10000 or 104 (cm) or × 10 × 1000; [1] PDO display 2 figure to no more than three sig. figs.; mm/cm 28/2.8 28.5/2.85 29/2.9 29.5/2.95 30/3 Reject use or conversion to metres Reject if no units [1]

Page 9 Mark Scheme: Teachers’ version Syllabus Paper GCE AS/A LEVEL – May/June 2010 9700 35 © UCLES 2010 (b) Make a large drawing of three of these structures, which must be complete, to show the differences between them. Draw a circle on Fig. 2.2 around each of the structures Z which you have drawn. MMO collection 1 circles 3 complete Z structures on Fig 2.2 AND draws three; Reject if overlaps text of question [1] PDO layout 1 clear, sharp, unbroken lines AND no shading large; [1] two of six structures match those drawn for shape; [1] MMO decisions 2 one enclosure matches any one structure shape AND position; Reject if more detail [1] Total [17]